Big arity lambda calls in IR look like standard method calls to an `invoke` with N arguments. However, this method doesn't exist in JVM, so instead we need to extract a call to `FunctionN.invoke(Object[])`.
These are extracted as "throw new kotlin.NoWhenBranchFoundException();", which is the Java lowering of the intrinsic.
In the process, amend the control-flow graph to let when branches propagate `throw`s outwards, and similarly statement expressions.
- Create a new operator representing an infix value [in]equality test, equivalent to Objects.equals(lhs, rhs)
- Continue to use simple equality where it is clearly possible at the callsite
- Note that ieee754equals is the same as Java's == and != operators
If it is used by the compiler to implement the infix plus operator, resugar it and extract a `+` as Java would. If it is literally called by the user (e.g. `(if (x) then "not null" else null).plus(something)`), then extract a call to the real method Intrinsics.stringPlus (a two-arg static method).
